1. Field of the Invention
The invention relates to a control apparatus and control method for an internal combustion engine. More specifically, the invention relates to a control apparatus and control method for an internal combustion engine in which a secondary air supply apparatus is provided.
2. Description of the Related Art
A secondary air supply apparatus is known, which supplies an exhaust manifold of an engine with secondary air delivered under pressure from an air pump so that CO and HC in exhaust gas are burned and changed to CO2 and H2O due to chemical reaction.
Japanese Patent Application Publication No. JP 2003-83048 discloses a secondary air supply apparatus in which it can be determined whether an abnormality has occurred in a component of the secondary air supply apparatus. The secondary air supply apparatus disclosed in the Japanese Patent Application Publication No. JP 2003-83048 includes a secondary air supply passage for supplying secondary air to a portion upstream of an exhaust gas control device in an exhaust system of an internal combustion engine; a opening/closing portion which opens/closes the secondary air supply passage; a check valve which is provided downstream of the opening/closing portion; a pressure sensor which is provided in the secondary air supply passage; and an abnormality detecting portion which detects an abnormality in the component based on a pressure value detected by the pressure sensor and a pressure change value.
In the secondary air supply apparatus disclosed in the Japanese Patent Application Publication No. JP 2003-83048, since the pressure value and the pressure change value are obtained using the pressure sensor, a failure mode of each component can be determined in detail based on combination of the pressure value and the pressure change value.
However, in the secondary air supply apparatus disclosed in the Japanese Patent Application Publication No. JP 2003-83048, no consideration is given to a measure which should be taken when failure occurs in the component. Therefore, there is a problem that secondary failure may be caused due to failure in the component.